3. Draw the curve. A curve is then drawn from the 1 to 2 to 3 priority substituents, ignoring the 4th priority subsituent (as shown below). If that curve goes clockwise then that stereocenter is of the R configuration. If the curve goes in a counterclockwise direction, then that stereocenter is of S configuration. In our example below, the curve goes counterclockwise so the stereocenter is of S configuration.